How do you reset the SRS unit

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  • amusa
    Junior Member
    • Feb 2019
    • 3

    How do you reset the SRS unit

    2004 Mercedes-Benz CLK500 was left in below 10 degree weather outside and triggered the SRS system (light on). I pulled the codes but can't clear it. Since the SRS unit behind the ashtray is not communicating. This vehicle never had a airbag deployed.

    Here is the codes that I pulled
    B107C, Tele Aid ECU - A35/8 Fault In Communication
    B1076, Upper Control Panel ECU - N72/1 Control unit
    B1041, Driver Knee bag Ignition Squib - R12/25 Ignition Circuit Resistance Value Wrong
    B1043, Restraint Systems ECU - N2/7 Coding is Faulty
    B105B, Restraint Systems ECU - N2/7 Coding is Faulty
    B1072, Front Right Child/Passenger Seat Occupation - B48 Coding is Faulty
    B1055, Driver Side Seat Buckle Switch - S68/3 Short Circuit to Battery Voltage or Open Circuit
    B1058, Passenger Side Seat Buckle Switch - S68/4 Short Circuit to Battery Voltage or Open Circuit
    B106D, Front Right Child/Passenger Seat Occupation - B48 Short circuit to ground
    B106C, Front Right Child/Passenger Seat Occupation - B48 Fault in Communication.


    Keep in mind that B1041, This vehicle never came with Driver Knee bag Ignition Squib.

    How do you reset the SRS unit or reprogram? Is this something I need to have a Mercedes STAR diagnostic tool to do it?
  • Glide
    Senior Member
    • Jan 2015
    • 303

    #2
    If the SRS unit isn't communicating you will have to find out why and fix that problem first.You can't program it or clear codes if it won't communicate.
    Maybe a mouse got in and chewed some wiring?After the car was left in the cold did you have to boost the battery?

    Comment

    • amusa
      Junior Member
      • Feb 2019
      • 3

      #3
      Originally posted by Glide
      If the SRS unit isn't communicating you will have to find out why and fix that problem first.You can't program it or clear codes if it won't communicate.
      Maybe a mouse got in and chewed some wiring?After the car was left in the cold did you have to boost the battery?
      The vehicle started up with no issue. I did not touch the battery at all. I'm going to dive into it and pull the SRS unit out and check each wire. If this does not resolved it. I'm taking it to my friend (Mercedes Tech) that owns a Star tool. I see if he can unlock the unit and re-coded it.

      Comment

      • Witsend
        Banned
        • Nov 2012
        • 2942

        #4
        The vehicle started up with no issue. I did not touch the battery at all. I'm going to dive into it and pull the SRS unit out and check each wire. If this does not resolved it. I'm taking it to my friend (Mercedes Tech) that owns a Star tool. I see if he can unlock the unit and re-coded it.
        Before the car kicks your @ss, you might want to check the fuse box under hood at the firewall and inside, sometimes some of the fusebox terminals just have a meltdown.

        Last edited by Witsend; 02-08-2019, 07:07 PM.

        Comment

        • amusa
          Junior Member
          • Feb 2019
          • 3

          #5
          I did check all (4) fuse and there good (I use a test light).

          Update:
          My friend over at Mercedes ran the STAR tool. He said the B1041, Driver Knee bag Ignition Squib - R12/25 Ignition Circuit Resistance Value Wrong. This code only apply to the Cabriolet (convertibles) only (this vehicle is a coupe).

          He tried to reset and clear out these codes and cannot. He said the SRS unit is locked up and in need of a new unit.

          Comment

          • Witsend
            Banned
            • Nov 2012
            • 2942

            #6
            I did check all (4) fuse and there good (I use a test light).
            Fuses still could test fine with a test light, but the load side terminal inside the fuse box might have corroded and burnt. Best to still actually remove and visually inspect fuses and look at the spades and on both sides and the female terminals of the fuse box each insert into.

            Comment

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